Copyright © Françoise Herrmann
The crimped and cut design retained for Melitta® paper filters, to this day, was originally recited nearly 100 years ago.
As recited in GB451197, granted on July 31, 1936, to Horst Wolfgang Bentz (Melitta’s son), the Melitta® paper filter resolved several problems of the prior art. In particular, the way in which prior art paper filters decreased the rate of filtering because when pressed into the ribbed filtering cup, the paper doubled or tripled in thickness on the walls of the ribbed cup. In turn, the excess paper, thus used, also increased waste and costs. Additionally, prior art paper also tended to tear when the filtering cup was wet.
together into a cone-shaped vessel. (recited alternatively as glued, goffered, stitched or stamped), In one embodiment of the invention, a variation of which is retained to date, the apex of the cone-shaped filter is either folded back on the side (fig. 5), or cut and crimped (fig. 3), like the edges of the filter walls. In another (un-retained) embodiment of the invention (fig. 6), the bottom of the filter is separately cut and attached by means of crimping (goffering, stamping, gluing, etc.)
The image of a commercially available, cut and crimped, 2017 box of size 4 Melitta® paper filters is also included above.